NMR spectroscopy will be developed as a method for structural studies of proteins in supramolecular structures and applied to the filamentous bacteriophages, especially phages with coat proteins displaying designed and selected peptides on their surface. The research plan for the next funding period reflects the success in developing solid-state NMR spectroscopy for the study of proteins achieved with the support of this grant, the greatly improved capabilities of a newly constructed high-field solid-state NMR spectrometer dedicated to these studies, and recent developments in the molecular biology of filamentous bacteriophages, which enable them to display peptide sequences inserted into the major pVIII coat protein. The major area of spectroscopic development continues to be solid-state NMR method for determining the structures of proteins. The approach receiving the greatest attention is for samples where the proteins are immobile and uniaxially oriented in the magnetic field of the spectrometer. Complementary spectroscopic methods will be developed which utilize magic angle sample spinning on samples where the proteins are immobile and unoriented. Methods for using solid-state NMR spectroscopy to characterize the backbone dynamics of proteins will also be developed. Motional averaging of powder pattern lineshapes will be supplemented with relaxation measurements. Molecular dynamics simulations with and without experimental restraints are an integral part of the research plan. The proposed studies exploit several unique biological and physical properties of filamentous bacteriophages, especially the folding and immobilization of the inserted peptide sequences in the environment of the coat proteins and the spontaneous orientation of the phages in the magnetic field of the NMR spectrometer. Studies of these peptides are of interest from the perspectives of protein folding, epitope characterization, and receptor binding. Peptide sequences important to understanding diseases as diverse as malaria, cancer, and H.I.V. will be investigated.